This invention relates to a wire rope spreader used for handling and spreading two steel wire rope construction slings from a common crane hook.
A steel wire rope sling will typically become kinked and deformed through normal use, thereby making the sling difficult to handle by the labor force. Additionally, one inherent characteristic of steel wire rope is that it will usually rotate and spin away from the preformed lay of the rope when loaded and spin in the opposite direction when unloaded. Consequently, when a pair of steel wire rope slings are attached to a common hoist or crane hook they will tend to wrap around each other. The above conditions will make rigging jobs very awkward and sometimes dangerous when performing both routine and non-routine rigging jobs. The time lost in handling and untangling the slings weighs heavily on the productivity of the labor force.
Standard rigging practices and methods will almost never directly address the problem of twisted and tangled slings. Certain futile attempts have been made to utilize conventional spreader bars to separate the slings, but they develop their own unique problems associated with extreme size, weight and rigid characteristics. Furthermore, lifting frames or spreader bars are indeed primarily engineered to accommodate certain carried materials/equipment for their structural integrity or for their safety and not for spreading slings. The actual benefit of having the slings hang free and unencumbered using a conventional lifting frame or rigid spreader bar is minimal.
A lifting device which features a method of separating the slings is illustrated in the patent to G. L. Corbett ("Applicant"), U.S. Pat. No. 4,239,272. The Corbett device does not deal with many of the various job situations primarily because it is a lifting device and the slings are included in the design, making it too restrictive and cumbersome to be practical in its use industry-wide. Additionally, the said device uses a predetermined size and length for the working slings; consequently, one may need to add slings and hardware to the device to suit his rigging requirements.
What is needed is a small, portable and convenient tool which is specifically suited to keep a pair of wire rope slings from becoming twisted or tangled while hanging from a mechanical hoist.